1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to determining a power limited mode for operating a device.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks. Furthermore, UMTS supports multiple radio access bearer (multi-RAB) capability, which simultaneous network communication with a user equipment (UE) over two or more radio access bearers. Therefore, multi-RAB functionality in UMTS allows for a user equipment to concurrently transmit and receive packet-switched and circuit-switched data.
In some wireless networks, a device can utilize transport format combinations (TFC) for associating to transport channels for communicating with one or more base stations. The TFCs can employ associated states, such as a supported state, excess power state, or blocked state, to indicate whether the device can communicate over a transport channel based on the associated TFC. State transitioning for the TFCs is defined such that the state for a period of time is determined based on slot level transmit power measurements over multiple previous periods of time. Thus, it is possible that a state for a given TFC can fluctuate between a supported state and an unsupported state (e.g., excess power or blocked), where the slot level transmit power measurements fluctuate across a threshold defined for determining the supported or unsupported state. This can result in a TFC being set to a supported state where transmit power may not be at the threshold to operate in such a supported state, which can cause a reset in the radio link control (RLC) layer, referred to as an RLC reset, and eventually RLC unrecoverable errors. This also may cause a call drop for a circuit-switched (CS) call and a packet-switched (PS) call.
There are multiple techniques to limit the data associated with a PS call during power limited conditions or challenging radio conditions to ensure that a CS call will not be dropped. For example, one technique includes limiting the PS traffic based on non-minimum set TFCs being in an excess power or blocked state. The typical prior art solutions are not efficient, however, as they tend to unnecessarily block all PS traffic. Thus, improvements in controlling transmission states of TFCs are desired.